Direct Injection huge drawback

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EightySix Four

EightySix Four

Diamond Member
Jul 17, 2004
5,122
52
91
Ronstang said:
Then they need to have exhaust scavengers take care of it like I do on the cars I build. You end up with a great running engine that has no build up and no contaminating of the air/fuel charge and you can retrofit these to any car....no passing emissions is another issue.
Click to expand...

Hypothesis:
It's not the oil, it's the EGR system.

Test:
Open head of DI motors with no EGR system.

Results:
No buildup

Theory:
It's not the oil, it's the EGR system.

Next step:
EGR delete on motor which is known to have problems.
 
Last edited:
D

Doggiedog

Lifer
Aug 17, 2000
12,780
5
81
I've got a 335i which has a twin turbo DI engine. Apparently, ethanol is the bane of this engine. DI engines need a high pressure fuel pump but apparently the high ethanol levels in gasoline corrodes components inside the HPFP in my model engine. I've had 2 HPFPs replaced already and my third one is going as well. I'm only at 10,000 miles as well.
 
Bignate603

Bignate603

Lifer
Sep 5, 2000
13,897
1
0
Doggiedog said:
I've got a 335i which has a twin turbo DI engine. Apparently, ethanol is the bane of this engine. DI engines need a high pressure fuel pump but apparently the high ethanol levels in gasoline corrodes components inside the HPFP in my model engine. I've had 2 HPFPs replaced already and my third one is going as well. I'm only at 10,000 miles as well.
Click to expand...

So BMW didn't realize that a huge amount of gas worldwide uses ethanol? That was a bit of an oversight.
 
amdhunter

amdhunter

Lifer
May 19, 2003
23,332
249
106
Bignate603 said:
So BMW didn't realize that a huge amount of gas worldwide uses ethanol? That was a bit of an oversight.
Click to expand...

I never got this either. I feel bad for the first folks who had their warranties voided for using "bad gas." It's insane that there is still a problem with the N54 fuel pumps.
 
EightySix Four

EightySix Four

Diamond Member
Jul 17, 2004
5,122
52
91
Doggiedog said:
I've got a 335i which has a twin turbo DI engine. Apparently, ethanol is the bane of this engine. DI engines need a high pressure fuel pump but apparently the high ethanol levels in gasoline corrodes components inside the HPFP in my model engine. I've had 2 HPFPs replaced already and my third one is going as well. I'm only at 10,000 miles as well.
Click to expand...

Have they not redesigned the replacement pumps yet? Seems dumb.
 
D

Doggiedog

Lifer
Aug 17, 2000
12,780
5
81
I think they've redesigned the pump two times already and switched manufacturers.

There's a new one out but I didn't get it the last time I had the pump replaced (in December). My 2nd pump started acting bad almost immediately. I took my car in 3 weeks ago for a new pump or so I thought but all they did was install new software (which took 2 days). The pump hasn't acted up but I'm wondering how much longer it has. My car feels very sluggish now compared to before. I'll bet the new software detuned the engine or pump somehow to increase its lifespan.
 
E

Eli

Super Moderator | Elite Member
Oct 9, 1999
50,419
8
81
This was an unforseen problem with Direct Injection. Apparently nobody realized just how much gasoline kept the intake tract clean.

I am sure they'll find ways around it, but it is indeed a problem right now. I hope it doesn't sway people away from Direct Injection engines. It is a good technology.
 
halik

halik

Lifer
Oct 10, 2000
25,696
1
81
PricklyPete said:
I didn't realize the B6/B7 S4's had direct injection...for some reason I was thinking only the RS4 version of the engine did. Interesting.
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The B6/B7 S4s do not, but audi makes a 2.0 TFSI also that has the same issue.
 
StageLeft

StageLeft

No Lifer
Sep 29, 2000
70,150
5
0
Doggiedog said:
I've got a 335i which has a twin turbo DI engine. Apparently, ethanol is the bane of this engine. DI engines need a high pressure fuel pump but apparently the high ethanol levels in gasoline corrodes components inside the HPFP in my model engine. I've had 2 HPFPs replaced already and my third one is going as well. I'm only at 10,000 miles as well.
Click to expand...
FVCK ME. I remember when you had to get the second replaced I think but you're about to have burned through a third? So, basically, your car goes through fuel pumps TWICE as fast as it does oil changes? Is this common with your car, surely most others with it aren't having this problem?
 
A

ayabe

Diamond Member
Aug 10, 2005
7,449
0
0
Doggiedog said:
I've got a 335i which has a twin turbo DI engine. Apparently, ethanol is the bane of this engine. DI engines need a high pressure fuel pump but apparently the high ethanol levels in gasoline corrodes components inside the HPFP in my model engine. I've had 2 HPFPs replaced already and my third one is going as well. I'm only at 10,000 miles as well.
Click to expand...

Damn, thought they had that figured out. This is the single biggest reason I don't have a 335i in my garage.
 
R

rancherlee

Senior member
Jul 9, 2000
707
18
81
It isn't a direct injection problem, hell Diesel engines have be direct injection for a LONG time. Its an control problem as Either the valve seals really suck or the PCV system is allowing too much oil to get into the intake system.
 
PricklyPete

PricklyPete

Lifer
Sep 17, 2002
14,582
162
106
halik said:
The B6/B7 S4s do not, but audi makes a 2.0 TFSI also that has the same issue.
Click to expand...

Gotcha. I thought you were saying that you had carbon build up on your S4 for this exact reason. I'm aware that the 2.0L DI engines at Audi/VW have this problem.
 
amdhunter

amdhunter

Lifer
May 19, 2003
23,332
249
106
ayabe said:
Damn, thought they had that figured out. This is the single biggest reason I don't have a 335i in my garage.
Click to expand...

Most BMW owners never have this problem, which makes me think there are other issues that is causing the failure on certain cars. It sucks that BMW's fix is to gimp your ride in the meantime.
 
ViviTheMage

ViviTheMage

Lifer
Dec 12, 2002
36,189
87
91
madgenius.com
AsianriceX said:
Here's a reference for VAG folks:
http://www.audizine.com/forum/showthread.php?336352-Audi-FSI-Engine-Carbon-Build-up-Megathread

Looks like Porsche isn't immune either:
http://forums.rennlist.com/rennforu...the-new-gt3-doesnt-have-direct-injection.html

I've heard that Mazdaspeed3/6 guys are having the same issues, but I'm too lazy to look that up right now.
Click to expand...

Yeah, I read that thread on audizine and got sad...something to look forward too I guess, LOL.

..granted, I am on 50k in my B7 2.0T and I haven't noticed any problems.
 
PricklyPete

PricklyPete

Lifer
Sep 17, 2002
14,582
162
106
ViviTheMage said:
Yeah, I read that thread on audizine and got sad...something to look forward too I guess, LOL.

..granted, I am on 50k in my B7 2.0T and I haven't noticed any problems.
Click to expand...

Once we get closer to the end of the warranty on our 2.0T, I'm going to take a look at these puppies. If it looks really bad, it may influence our decision on keeping it longer if they have not come up with a decent solution for this.
 
StageLeft

StageLeft

No Lifer
Sep 29, 2000
70,150
5
0
Veedubs aren't really meant to be kept past about 50k now. I'd just scrap it around then tbh
 
PricklyPete

PricklyPete

Lifer
Sep 17, 2002
14,582
162
106
Skoorb said:
Veedubs aren't really meant to be kept past about 50k now. I'd just scrap it around then tbh
Click to expand...

I plan on dropping a pimPrius drivetrain into it around 50K. If I can't get 50mpg out of it though, I'm not going to the gym.
 
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